Description ( provided by applicant): West Nile Virus infection of the central nervous system (WNV-CNS) is a potentially life-threatening and/or debilitating neurological illness. Current data from the Centers for Disease Control indicates that 9858 cases of WNV occurred during the year 2003, of which 2863 (29%) were classified as neuroinvasive disease. WNV infections in the state of Colorado accounted for 2947 (29.9%) of all reported WNV cases, among which 621 (21.1%) were of the neuroinvasive type. Although a variety of elemental neurologic, cognitive, emotional, and behavioral problems are known consequences of neuroinvasive WNV infections, the types, severities, and functional consequences of these problems are as yet incompletely understood. Spalding Rehabilitation Hospital, an acute rehabilitation facility located in Aurora, CO and affiliated with the University of Colorado Health Sciences Center (UCHSC), participated in the acute neurorehabilitation of 18 persons with WNV-CNS during the 2003 outbreak of this condition. Retrospective review of the clinical presentation and rehabilitation outcomes of these individuals suggest that WNV-CNS results in significant impairments in frontally-mediated cognition, modest impairments in memory, orientation, and language, a high frequency of neuropsychiatric symptoms such as impulsivity and anxiety, and functional impairments across both motor and cognitive domains. In light of several vector, animal host, and environmental factors in the front range of the Rocky Mountain region, WNV infections are anticipated to occur in relatively large numbers during 2004. Spalding Rehabilitation Hospital is expected to participate in the acute neurorehabilitation of a significant proportion of these individuals. The present proposal describes a prospective study of the neurological, neurobehavioral, and functional outcomes of WNV-CNS during the 2004 season for the purpose of obtaining information to clarify the clinical presentation of this condition and with which to guide future investigations into the diagnosis, treatment, and neurorehabilitation of these persons with this condition.